1. Field of the Invention
The present invention relates to pet leashes; and more particularly, to an omnidirectionally reflective pet leash especially suited for use during dusk or nighttime hours to enhance safety of pets and their owners while walking in the vicinity of land vehicles.
2. Description of the Prior Art
Walking a pet during dusk or nighttime hours can be hazardous in neighborhoods where automobiles are encountered. Illuminating characteristics of the automobile headlamps, generally afford an illumination range of approximately 25 to 50 feet. This illumination range can be significantly reduced by mist or fog, or bends in the road. Despite improvements to vehicle headlights, pets and their owners are oftentimes not recognized by automobile drives until the distance between the automobile and the pet is small.
Several approaches devised by prior art workers attempt to provide solutions for this hazardous common activity. These approaches include 1) use of pet collars that are illuminated or reflective; 2) use of leashes which are illuminated or reflective; or 3) a combination of both features. None of these solutions suggest indicating the whereabouts of a pet owner, a leash and a pet attached to the leash via omnidirectional reflection.
Various types of illuminated dog collars using bulb or other powered sources are known in the art. These power-illuminated leashes require batteries, light bulbs or other lighting elements, which are not needed for reflective illumination. Accordingly, a detailed discussion thereof is not required.
U.S. Pat. No. 4,173,201 to Chao et al. discloses an illuminated collar for pets and the like. U.S. Pat. No. 4,513,692 to Kuhnsman et al. discloses an illuminated pet leash comprising a non-opaque tube that contains one or more bundles of optical fibers. U.S. Pat. No. 4,895,110 to Lo Cascio discloses a pet collar that includes a light source and a power source attached to a strap. U.S. Pat. No. 4,887,552 to Hayden discloses an electrically lighted pet leash that is composed of a transparent, flexible tube containing a string of small electric light bulbs mounted in parallel between two insulated wires. U.S. Pat. No. 5,046,456 to Heyman et al. discloses an illuminated pet collar in which multiple lights are mounted within a flexible, light-permeable tube that extends about the perimeter of the collar. A housing mounted on one end of the tube contains a circuit and a battery for operating the lights. U.S. Pat. No. 5,140,946 to Pennock et al. discloses an illuminated pet collar with miniature lights powered by a battery encased within a flexible, pliable, transparent plastic display tube, which are parallel-wired within the display tube. U.S. Pat. No. 5,370,082, to Wade discloses an animal collar that includes illuminating devices, such as light emitting diodes, liquid quartz strips or electric lamps powered by a plurality of solar cells. U.S. Pat. No. 5,429,075 to Passarella et al. discloses a pet leash and flashlight combination. U.S. Pat. No. 5,523,927 to Gokey discloses an illuminated animal collar light emitting diode placed on the outer exterior of a collar powered by a battery. U.S. Pat. No. 5,535,106, issued to Tangen, discloses a lighted animal collar that includes a plurality of separate light emitting assemblies, or housings, at spaced intervals along the collar. U.S. Pat. No. 5,558,044 to Nasser, Jr. et al. discloses an illuminating leash handle with a flashlight. U.S. Pat. No. 5,630,382 to Barbera et al. discloses an illuminated pet harness having straps with internal cavities that contain fiber optic cores illuminated by a light bulb. U.S. Pat. No. 5,762,029 to DuBois et al. discloses a combined retractable leash and flashlight. U.S. Pat. No. 5,850,807 to Keeler discloses an illuminated pet leash, wherein illumination is remotely activated by a pet owner to locate the leash. U.S. Pat. No. 5,967,095 to Greves discloses an electroluminescence-illuminated pet flat leash strap. U.S. Pat. No. 6,170,968 to Caswell discloses a motion activated rotatable illuminator. U.S. Pat. No. 6,289,849 to Macedo et al. discloses a device for removably attaching a flashlight to a retractable dog leash. U.S. Pat. No. 6,557,498 to Smierciak et al. discloses a night safety pet illumination marker, with a pet collar having a series of light emitting diodes mounted around the perimeter of the collar and powered by battery power.
Various types of dog collars illuminated by reflection are known in the art. Representative dog collars of this variety are discussed below.
U.S. Pat. No. 3,871,336 to Bergman discloses a reflective dog collar which is not illuminated; but which utilizes a highly reflective material having the form of different color dots encapsulated in plastic. This illuminates only portions of the flat planar pet collar.
U.S. Pat. No. 3,999,521 to Puiello discloses a reflective safety harness for quadruped animals. The harness includes a pair of identical sheet elements with a light reflective surface mounted on opposite sides of the animal. At the corners of the sheet are fastened straps, which circumscribe the animal's body at the front and rear of the harness. Extending from the front strap, at the top point thereof, midway between the two elements, is a loop through which the dog's regular collar is passed. The arrangement assures immovable attachment of the harness on the dog's body. The disclosure by the '521 patent of a reflective sheet positioned on both sides of the animal does not suggest a pet collar or a leash that reflects incident light.
U.S. Pat. No. 4,167,156 to Kupperman et al. discloses a reflective animal leather leash. The elongated leather animal leash includes a sewn a transparent polyvinyl chloride strip with a light reflective prism design on one surface. The light reflective prism is bonded by dielectric heat sealing or sonic welding to an opaque polyvinyl chloride strip sewn to the leather strip, resulting in a leash having a light reflective surface. Since the strip has a reflective surface on only one side of the leash, it does not reflect light in every direction. The flat leather leash is not easily twistable and is not readily bent without separating the transparent and opaque polyvinyl chloride layers.
U.S. Pat. No. 4,384,548 to Cohn discloses a safety device for animals. A pet collar uses “retro-reflective” threads with glass reflective elements in a flexible webbing to form a pet leash. The threads are said to reflect incident light directly back toward the source. Disposition of reflective threads in the webbing forming the collar is sparce. As a result, the quantum of incident light reflected is small; and an insignificant quantum of incident light is reflected back to the source.
U.S. Pat. No. 4,407,233 to Bozzaco discloses a safety collar for pets. The collar has highly reflective flexible elements with a length large enough to extend beyond the outer surface of the pet's hair. It uses flexible elements with Scotchlite reflecting strips attached to a collar. A reflective pet leash is not disclosed, and the flexible elements do not reflect light in every direction.
U.S. Pat. No. 5,243,457 to Spencer discloses a material with enhanced visibility characteristics. This flexible visibility enhancing material combines the advantages of a light reflective component and a luminescent component. The material includes a first layer of prismatic light reflective plastic material having an underlying surface formed with a plurality of minute prism-like formations projecting there from at regular spaced intervals, and an overlying substantially smooth light transmissive surface. Bonded, i.e. by heat-sealing, to the first layer is a second layer of plastic luminescent material. The second layer is contiguously and integrally attached to the underlying surface of the prism-like formations and generally coextensive therewith. The visibility enhancing material simultaneously radiates luminescent light from the second layer through the underlying surface of prism-like formations and through the smooth light transmissive surface and reflects light from the prism-like formations through the smooth light transmissive surface. In one embodiment, a leash for controlling and restraining a pet animal includes a flexible elongate member comprised of the visibility enhanced material. In another embodiment, the second layer is replaced with a layer of luminescent material, which can be selectively energized to become luminous. Since the transparent reflective material is a molded plastic of prismatic construction it is rigid and is not flexible and does not form a leash that is capable of being twisted and bent. Further any twisting and bending action separates the reflective element from the luminescent element.
U.S. Pat. No. 5,237,448 to Spencer et al. discloses a visibility enhancing material. The flexible visibility enhancing material combines the advantages of a light reflective component and a luminescent component. The material includes a first layer of prismatic light reflective plastic material having an underlying surface formed with a plurality of minute prism-like formations projecting therefrom at regular spaced intervals, and an overlying substantially smooth light transmissive surface. A second layer of plastic luminescent material is contiguously and integrally attached to the underlying surface of the prism-like formations and generally coextensive therewith. The visibility enhancing material simultaneously radiates luminescent light from the second layer through the underlying surface of the prism-like formations and through the smooth light transmissive surface, and reflects light from the prism-like formations through the smooth light transmissive surface. In one embodiment, a leash for controlling and restraining a pet animal includes a flexible elongate member comprised of the visibility enhanced material. Since the transparent reflective material is a molded plastic of prismatic construction, it is rigid and is not flexible and does not form a leash that is capable of being twisted and bent. Furthermore, any twisting and bending action will result in separation of the reflective element from the luminescent element.
U.S. Pat. No. 6,070,556 to Edwards discloses an illuminating dog safety system. This illuminating dog safety system is designed for allowing an animal to be more visible at night. The device includes a collar that is worn around a neck of an animal. The collar has a reflective strip extending a majority of its length. A harness is provided that is adapted to be worn around a torso of the animal. The harness is comprised of an upper strap member, a lower strap member, and a longitudinal extension there between. The upper strap member, the lower strap member, and the longitudinal extension each have a reflective strip extending a majority of a length thereof. A leash is provided that is adapted for securement to the collar. The leash has a reflective strip extending a majority of its length. All these strip elements are made from flat elements, as shown in FIG. 3 of the patent disclosure. Twisting the elements does not provide the reflectivity needed for adequate visibility at night.
Numerous patents disclose reflective materials. Some of these patents disclose reflective elements having corner cube shapes embedded in a rigid or flexible polymeric strips and monolayers of spherical beads, i.e. primarily glass beads bonded to a reflective sheet.
U.S. Pat. No. 3,176,584 to DeVries et al. discloses that a reinforcing layer may be incorporated into an embedded lens retroreflective sheeting. The reinforcing layer may be of a similar composition as the binder in which the microspheres are embedded. The layer may be applied to the back side of the secularly reflective layer via spraying, i.e., by a solvent-coating technique. Examples of the reinforcing layer materials disclosed include methyl methacrylate, flexible epoxy resins, chloro-sulfonated polyethylene, polystyrene, polypropylene, polycarbonate resin, ethyl cellulose, and cellulose acetate-butyrate. The reflective layer is typically very thin and fragile, i.e. in the order of 0.06 microns thick, and must be disposed in special relationship to the microspheres in order for the sheeting to provide useful retro-reflection.
U.S. Pat. No. 3,190,178 to McKenzie discloses a reflex reflective sheeting. It uses a monolayer of microspheres embedded in a polymer to reflect the incoming light beam in the same direction as the incident beam. Since the sheet is formed by melting of the polymeric binder, it is rigid and therefore unsuitable for flexible pet leashes.
U.S. Pat. No. 4,025,159 to McGrath discloses cellular retroreflective sheeting. The cellular retroreflective sheeting comprises a base layer of retroreflective elements and a transparent cover film supported in spaced relation away from the base layer by a network of narrow intersecting bonds. These bonds form hermetically sealed cells within which retroreflective elements are isolated from retroreflective elements of different cells. The resultant sheeting achieves greater durability through use of bonds that are cured in situ after they have been thermoformed into sealing contact between the cover film and base layer. The base material is coated with the binder, subjected to heat and pressure to displace the binder around the embedded microsphers or corner cubes forming the bonded network. Retroreflective articles so constructed may be rigid and inflexible.
U.S. Pat. No. 4,576,850 to Martens, and U.S. Pat. Nos. 4,582,885, 4,668,558 to Barber disclose a shaped plastic articles having replicated microstructure surfaces. This shaped plastic article is made by crosslinked polymer with hard and soft segments having a microstructure-bearing surface that is replicated, with a castable fluid, and radiation hardened. Articles formed by this process exhibit, a retro-reflective cube-corner sheeting, Fresnel lens or video disc. All these formed articles are rigid and therefore unsuitable for use in pet leashes. Moreover, these articles also exhibit low tear strength.
U.S. Pat. No. 4,763,985 to Bingham discloses a launderable retroreflective appliqué that comprises a layer of transparent microspheres, a specular reflective layer optically connected to each microsphere, and a binder layer into which the microspheres are partially embedded. Resins disclosed as being suitable for use as binder layers include polyurethane, polyesters, polyvinyl acetate, polyvinyl chloride, acrylics, or combinations thereof. The specular reflective layers are composed of two succeeding layers of dielectric material. The layers have varying refractive indices and are composed of a variety of binary metal compounds including oxides, sulfides, and fluorides.
U.S. Pat. No. 4,957,335 to Kuney discloses microsphere-based retro-reflective articles having high retroreflective brightness at narrow divergence or observation angles, i.e. up to 0.5 degrees. The article is made by selection of microspheres having defined combinations of average diameter and average refractive index. This patent teaches (column 4, lines 18–23) that variation in the size of the microspheres will increase the observation angle or divergence angle of the resultant retro-reflective article.
U.S. Pat. No. 5,066,098 to Kult et al. discloses cellular encapsulated-lens high whiteness retroreflective sheeting with a flexible cover sheet. This cellular, encapsulated-lens retroreflective sheeting comprises a base sheet of a monolayer of retroreflective elements that is partially embedded in a binder layer which typically is white. A cover sheet is disposed in spaced relation from the layer of retroreflective elements. A network of narrow intersecting bonds, or seal legs, that extend between the cover sheet and the base sheet with binder material are thermoformed at the point of contact between the base sheet and cover sheet. Such a rigid, reflective sheet is unsuitable for pet leashes, which require structures that can twist and flex.
U.S. Pat. No. 5,117,304 to Huang et al. discloses a retroreflective article. The retroreflective article has corner cubes and is flexible, and can be applied over irregular surfaces by using an optically clear, aliphatic polyurethane polymer. The aliphatic polymer has a plurality of hard chain segments having the formula —C(O)N(H)—C6H10—N(H)C(O)—.
U.S. Pat. No. 5,200,262 to Li discloses a launderable retroreflective appliqué. The appliqué employs a reflector that comprises elemental aluminum or elemental silver on the backside of the microspheres. The appliqué comprises a monolayer of metal-coated microspheres partially embedded in and partially protruding from a binder layer. The binder layer comprises a flexible polymer having hydrogen functionalities and one or more isocyanate-functional silane coupling agents. The disclosed flexible polymers that possess hydrogen functionalities are crosslinked, flexible urethane-based polymers, such as isocyanate-cured polymers or one or two component polyurethanes and polyols.
U.S. Pat. No. 5,283,101 to Li discloses a launderable retroreflective appliqué comprising a binder layer formed from an electron-beam curable polymer and typically one or more crosslinkers and silane coupling agents. Electron-beam curable polymers include chlorosulfonated polyethylenes, ethylene copolymers comprising at least about 70 weight percent of polyethylene, such as ethylene/vinyl acetate, ethylene/acrylate, and ethylene/acrylic acid, and poly(ethylene-co-propylene-co-diene) polymers. Glass microspheres are embedded in the cured binder layer, and a specular reflective metal layer is disposed on the embedded portions thereof. When the appliqué is inverted, light comes through the binder layer.
U.S. Pat. No. 5,777,790 to Nakajima discloses a microsphere-based retroreflective article. The retroreflective article comprises a monolayer of microspheres partially embedded in and protruding from a binder layer and specular reflector underlying the microspheres. The monolayer of microspheres comprises a mixture of a first class of microspheres having a first refractive index and a second class of microspheres having a second refractive index. The second refractive index is higher than the first refractive index. As a result, the sheeting exhibits superior observation angle angularity.
U.S. Pat. No. 5,882,796 to Wilson et al. discloses bonded structured retroreflective sheeting. The structured retroreflective sheeting includes an array of corner cube structured retroreflective elements, a thermoplastic sealing film located proximate the structured elements, and bonding agent between the sealing film and the structured retroreflective elements. The bonding agent bonds the sealing film to the structured retroreflective film. This bonded structure is rigid and is unlikely to survive the flexing and twisting movements of a pet leash.
U.S. Pat. No. 5,926,314 to Smith et al. discloses a retroreflective cube corner article having scalene base triangles. The cube corner retroreflective article exhibits a wide range of retroreflective entrance angularity in at least one plane, and preferably in two or more planes. The structured surface has an array of cube corner elements formed by three intersecting sets of substantially parallel grooves. Each cube corner element includes a base triangle bonded by one groove from each of the three intersecting groove sets, the base triangle being scalene. The corner cube reflector is rigid and cannot be used for producing reflective leashes.
U.S. Pat. No. 5,962,108 to Nestegard et al. discloses a retroreflective polymer coated flexible fabric material and method of manufacture. The retroreflective polymeric coated flexible fabric material has a retroreflective layer and a polymeric compatibilizing layer welded to a polymeric coated outer surface of a flexible fabric material. The compatibilizing layer provides an intermediate layer between the retroreflective layer and the flexible fabric material, creating suitable bond strength between dissimilar polymers. Flexible fabric materials are polyester, nylon or cotton. The fabric is coated with highly plasticized polyvinyl chloride (PVC) or ethylene acrylic acid copolymer (EAA). These polymers are flexible, durable, and resistant to abrasion. The retroreflective prismatic elements layer includes: acrylic polymers, such as poly(methylmethacrylate); polycarbonates; cellulosics; polyesters such as poly(butyleneterephthalate); poly(ethyleneterephthalate); fluoropolymers; polyamides; polyetherketones; poly(etherimide); polyolefins; poly(styrene); poly(styrene) co-polymers; polysulfone; urethanes, including aliphatic and aromatic polyurethanes; and mixtures of the above polymers such as a poly(ester) and poly(carbonate) blend, and a fluoropolymer and acrylic polymer blend. The compatibilizing layer that is suitable for bonding between a retroreflective layer and a flexible fabric material include: polyurethane, ethylene methyl acrylate copolymer, ethylene N-butyl acrylate copolymer, ethylene ethyl acrylate copolymer, ethylene vinyl acetate copolymer, polymerically plasticized PVC, and polyurethane primed ethylene acrylic acid copolymer. Such a reflective fabric does not suggest the shape, construction or function of a pet leash.
U.S. Pat. No. 5,910,858 to Frey discloses retroreflective sheeting with a coated back surface. The retroreflective sheet has a plurality of indentations on the back surface to reflect the light, and a transparent front surface to encapsulate and protect the light reflecting indentations. This reflective sheet is rigid and is unsuitable for use in pet leashes.
Notwithstanding the efforts of prior art workers to construct pet leashes and pet collars that are illuminated by incident light, there remains a need in the art for a flexible pet leash that omnidirectionally reflects a significant quantum of incoming light back to its source. Numerous methods for producing retroreflectors have been disclosed. A flexible pet leash having a robust construction that withstands tensile and torsional forces attending leash usage, has long been needed in the art. Also needed is a flexible, omnidirectional pet leash capable of maintaining high reflectivity when subjected to surface abrasion from frictional forces created by contact of the leash with objects having rough exteriors, such as the ground, flooring, posts, trees and the like.